From c33ef43a359001415032665dfcd433979c462b71 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 8 Jun 2022 16:40:34 +0200 Subject: rcu/context-tracking: Remove unused and/or unecessary middle functions Some eqs functions are now only used internally by context tracking, so their public declarations can be removed. Also middle functions such as rcu_user_*() and rcu_idle_*() which now directly call to rcu_eqs_enter() and rcu_eqs_exit() can be wiped out as well. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Neeraj Upadhyay Cc: Uladzislau Rezki Cc: Joel Fernandes Cc: Boqun Feng Cc: Nicolas Saenz Julienne Cc: Marcelo Tosatti Cc: Xiongfeng Wang Cc: Yu Liao Cc: Phil Auld Cc: Paul Gortmaker Cc: Alex Belits Signed-off-by: Paul E. McKenney Reviewed-by: Nicolas Saenz Julienne Tested-by: Nicolas Saenz Julienne --- kernel/context_tracking.c | 98 +++++++++++++---------------------------------- 1 file changed, 27 insertions(+), 71 deletions(-) (limited to 'kernel/context_tracking.c') diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 072c4b6044b3..e485b6b01537 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -189,17 +189,17 @@ static void noinstr rcu_eqs_exit(bool user) } /** - * rcu_nmi_exit - inform RCU of exit from NMI context + * ct_nmi_exit - inform RCU of exit from NMI context * * If we are returning from the outermost NMI handler that interrupted an * RCU-idle period, update ct->dynticks and ct->dynticks_nmi_nesting * to let the RCU grace-period handling know that the CPU is back to * being RCU-idle. * - * If you add or remove a call to rcu_nmi_exit(), be sure to test + * If you add or remove a call to ct_nmi_exit(), be sure to test * with CONFIG_RCU_EQS_DEBUG=y. */ -void noinstr rcu_nmi_exit(void) +void noinstr ct_nmi_exit(void) { struct context_tracking *ct = this_cpu_ptr(&context_tracking); @@ -242,7 +242,7 @@ void noinstr rcu_nmi_exit(void) } /** - * rcu_nmi_enter - inform RCU of entry to NMI context + * ct_nmi_enter - inform RCU of entry to NMI context * * If the CPU was idle from RCU's viewpoint, update ct->dynticks and * ct->dynticks_nmi_nesting to let the RCU grace-period handling know @@ -250,10 +250,10 @@ void noinstr rcu_nmi_exit(void) * long as the nesting level does not overflow an int. (You will probably * run out of stack space first.) * - * If you add or remove a call to rcu_nmi_enter(), be sure to test + * If you add or remove a call to ct_nmi_enter(), be sure to test * with CONFIG_RCU_EQS_DEBUG=y. */ -void noinstr rcu_nmi_enter(void) +void noinstr ct_nmi_enter(void) { long incby = 2; struct context_tracking *ct = this_cpu_ptr(&context_tracking); @@ -302,32 +302,33 @@ void noinstr rcu_nmi_enter(void) } /** - * rcu_idle_enter - inform RCU that current CPU is entering idle + * ct_idle_enter - inform RCU that current CPU is entering idle * * Enter idle mode, in other words, -leave- the mode in which RCU * read-side critical sections can occur. (Though RCU read-side * critical sections can occur in irq handlers in idle, a possibility * handled by irq_enter() and irq_exit().) * - * If you add or remove a call to rcu_idle_enter(), be sure to test with + * If you add or remove a call to ct_idle_enter(), be sure to test with * CONFIG_RCU_EQS_DEBUG=y. */ -void noinstr rcu_idle_enter(void) +void noinstr ct_idle_enter(void) { WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !raw_irqs_disabled()); rcu_eqs_enter(false); } +EXPORT_SYMBOL_GPL(ct_idle_enter); /** - * rcu_idle_exit - inform RCU that current CPU is leaving idle + * ct_idle_exit - inform RCU that current CPU is leaving idle * * Exit idle mode, in other words, -enter- the mode in which RCU * read-side critical sections can occur. * - * If you add or remove a call to rcu_idle_exit(), be sure to test with + * If you add or remove a call to ct_idle_exit(), be sure to test with * CONFIG_RCU_EQS_DEBUG=y. */ -void noinstr rcu_idle_exit(void) +void noinstr ct_idle_exit(void) { unsigned long flags; @@ -335,18 +336,6 @@ void noinstr rcu_idle_exit(void) rcu_eqs_exit(false); raw_local_irq_restore(flags); } -EXPORT_SYMBOL_GPL(rcu_idle_exit); - -noinstr void ct_idle_enter(void) -{ - rcu_idle_enter(); -} -EXPORT_SYMBOL_GPL(ct_idle_enter); - -void ct_idle_exit(void) -{ - rcu_idle_exit(); -} EXPORT_SYMBOL_GPL(ct_idle_exit); /** @@ -431,50 +420,11 @@ void ct_irq_exit_irqson(void) ct_irq_exit(); local_irq_restore(flags); } - -noinstr void ct_nmi_enter(void) -{ - rcu_nmi_enter(); -} - -noinstr void ct_nmi_exit(void) -{ - rcu_nmi_exit(); -} +#else +static __always_inline void rcu_eqs_enter(bool user) { } +static __always_inline void rcu_eqs_exit(bool user) { } #endif /* #ifdef CONFIG_CONTEXT_TRACKING_IDLE */ -#ifdef CONFIG_NO_HZ_FULL -/** - * rcu_user_enter - inform RCU that we are resuming userspace. - * - * Enter RCU idle mode right before resuming userspace. No use of RCU - * is permitted between this call and rcu_user_exit(). This way the - * CPU doesn't need to maintain the tick for RCU maintenance purposes - * when the CPU runs in userspace. - * - * If you add or remove a call to rcu_user_enter(), be sure to test with - * CONFIG_RCU_EQS_DEBUG=y. - */ -noinstr void rcu_user_enter(void) -{ - rcu_eqs_enter(true); -} - -/** - * rcu_user_exit - inform RCU that we are exiting userspace. - * - * Exit RCU idle mode while entering the kernel because it can - * run a RCU read side critical section anytime. - * - * If you add or remove a call to rcu_user_exit(), be sure to test with - * CONFIG_RCU_EQS_DEBUG=y. - */ -void noinstr rcu_user_exit(void) -{ - rcu_eqs_exit(true); -} -#endif /* #ifdef CONFIG_NO_HZ_FULL */ - #ifdef CONFIG_CONTEXT_TRACKING_USER #define CREATE_TRACE_POINTS @@ -542,7 +492,13 @@ void noinstr __ct_user_enter(enum ctx_state state) * that will fire and reschedule once we resume in user/guest mode. */ rcu_irq_work_resched(); - rcu_user_enter(); + /* + * Enter RCU idle mode right before resuming userspace. No use of RCU + * is permitted between this call and rcu_eqs_exit(). This way the + * CPU doesn't need to maintain the tick for RCU maintenance purposes + * when the CPU runs in userspace. + */ + rcu_eqs_enter(true); } /* * Even if context tracking is disabled on this CPU, because it's outside @@ -579,7 +535,7 @@ void ct_user_enter(enum ctx_state state) /* * Some contexts may involve an exception occuring in an irq, * leading to that nesting: - * ct_irq_enter() rcu_user_exit() rcu_user_exit() ct_irq_exit() + * ct_irq_enter() rcu_eqs_exit(true) rcu_eqs_enter(true) ct_irq_exit() * This would mess up the dyntick_nesting count though. And rcu_irq_*() * helpers are enough to protect RCU uses inside the exception. So * just return immediately if we detect we are in an IRQ. @@ -631,10 +587,10 @@ void noinstr __ct_user_exit(enum ctx_state state) if (__this_cpu_read(context_tracking.state) == state) { if (__this_cpu_read(context_tracking.active)) { /* - * We are going to run code that may use RCU. Inform - * RCU core about that (ie: we may need the tick again). + * Exit RCU idle mode while entering the kernel because it can + * run a RCU read side critical section anytime. */ - rcu_user_exit(); + rcu_eqs_exit(true); if (state == CONTEXT_USER) { instrumentation_begin(); vtime_user_exit(current); -- cgit v1.2.3-58-ga151